This is mostly an extremely hacky PicoSystem emulator.
./DERP_SDL file.uf2
(To run some uf2s built with the PicoSystem SDK add --board pimoroni_picosystem before the file to override the board value)
A copy of the RP2040 bootrom is required in bootrom.bin.
This can be created from the elf files in the official releases:
arm-none-eabi-objcopy -O binary b2.elf bootrom.bin
... or dumped from a real RP2040 with picotool:
picotool save -r 0 4000 bootrom.bin
| Feature | Status | Details |
|---|---|---|
| Display | Hack | No SPI, hook in PIO code. Enough display regs implemented to guess 32blit vs picosystem SDK |
| Buttons | Works | |
| Sound | Works | |
| LED | TODO |
| Feature | Status | Details |
|---|---|---|
| Cortex-M0+ | Partial | Copied from GBA emu, so some details are still an ARM7 |
| DMA | Minimal | Implemented just enough for PicoSystem display updates |
| Clocks | Partial | |
| XOSC | Minimal | Fixed 12MHz |
| ROSC | Minimal | Fixed 6MHz |
| PLL | Partial | |
| GPIO | Partial | Missing overrides, partial interrupt handling |
| PIO | Minimal | Some status flags, fakes TX progress |
| USB | Partial | Optional device enumeration and USBIP server |
| UART | Minimal | Prints TX data |
| I2C | Minimal | Some registers stubbed |
| SPI | Minimal | SPI0 TNF always set |
| PWM | Partial | Enough for PicoSystem beeps |
| Timer | Partial | |
| Watchdog | Partial | Tick generation and reset timer |
| RTC | Minimal | Enough to get through init |
| ADC | None | |
| SSI | Minimal | Just enough to boot |
Additional boards with some support:
| Name | --board | Details |
|---|---|---|
| Pico | pico or default |
No extra peripherals, so no output |
| Interstate75 | pimoroni_interstate75 |
Emulates a single 32x32 panel. |
| Tufty2040 | pimoroni_tufty2040 |
Similar display hacks to PicoSystem |
A GDB server can be enabled on port 3333 with:
./DERP_SDL --gdb --board [board name]
To use this with Cortex-Debug, replace "servertype": "openocd" with
"servertype": "external",
"gdbTarget": "localhost:3333",Optional USB support can be enabled with:
./DERP_SDL --usb [...]
This will attempt to enumerate the device and print the output from a CDC interface if found.
Alternatively:
./DERP_SDL --usbip [...]
Will enable a USBIP server. Which can be connected to using something like:
(May require some extra sudo)
modprobe vhci-hcd
# check for devices
usbip list -r localhost
# attach device
usbip attach -r localhost -b 1-1Launching without a .uf2 file does allow using the bootrom's loader. Though this is probably not a good idea...
(Low level transfers/timings are not implemented so the transfer rate for USB data is... unpredictable)